The invention relates to end connectors used to connect cables to equipment ports, terminals or the like. The invention is particularly useful in, although not limited to, end connectors for coaxial cables in the cable television industry.
The conventional coaxial cable usually consists of a centrally located inner electrical conductor surrounded by and spaced inwardly from an outer electrical conductor. A dielectric insulator is interposed between the inner and outer conductors, with the outer conductor being surrounded by a protective dielectric jacket. The outer conductor can comprise a sheath of fine braided metallic strands, a metallic foil, or multiple layer combinations of either or both.
The conventional end connector is generally tubular in configuration, with a front end including a coupling nut which is adapted to attach to equipment ports or terminals, and with a rear end adapted to receive and attach to the cable.
Other connectors are adapted to push on rather than thread on the signal ports, have been presented. These push on type end connectors typically utilize a split ferrule configuration which includes a plurality of resilient fingers that enable relatively easy connection and disconnection of the end connector to the signal port. The split ferrule may be provided with a surrounding locking sheath which enhances the connection to the signal port.
Examples of such end connectors are described in U.S. Pat. Nos. 4,990,106, 5,073,129, and 5,195,906, of common assignee, and incorporated herein by reference.
Certain disadvantages relating to signal loss may be associated with end connectors that use the coupling nut. The mechanical interengagement between the coupling nut with the other components of the end connector are typically configured with coacting flat surfaces that allow for slight signal loss. For example, the coupling nut includes a flange which is rotatably supported by an opposing flange associated with a post arrangement. Ideally, the interactive surfaces of these flanges are brought into close contact with one another when the coupling nut is threaded onto the signal port. However, the coupling nut is often not properly or completely connected to the signal port, thus leaving a space which accommodates signal loss. In addition, the tolerances in manufacturing the flange surfaces may be less than ideal, which also provides paths for signal loss.
The standard sized threads associated with both the coupling nut and the signal port inherently have low reverse holding power. The threaded components, without the aid of specific locking devices, can be tightened to a point of creating a holding pressure between the mating threads. The tightening action is in an axial direction, thus the flat surfaces of the threads mate with one another as the connector components are drawn together. However, the high axial forces required to provide holding pressures can damage or destroy the threads of either the coupling nut or the signal port. Furthermore, extreme vibrations and temperature variations, as well as craftsmanship errors, may also cause the coupling nut to loosen from the signal port. Due to this loosening, signals normally entrapped within the connector begin leaking through opened crevices, thus escaping and creating interference with signal transmissions.
The principal objective of the present invention is to provide an improved end connector designed to ensure precise port connections which eliminate signal loss.
It is another object of the present invention to provide an end connector with a coupling nut which produces a high reverse or loosening force while protecting the connector and port components.
It is a further object of the present invention to provide a signal seal and locking effect with components of an end connector with the use of surface interferences between adjacent components.